Screw-jack



(No Model.)

\ J. 0. JQYGE.

SCREW JACK.

Patented Oct. 2, 1888'.

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UNITED STATES" PATENT OFFICE.

JACOB 0. Joyce, or DAYTON, OHIO.

SCREW-JACK.

SPECIFICATION forming part of Letters Patent No. 390.609, dated October2, 1888.

Application filed May 3, 1888. Serial No. 272,717. (No model.)

To aZZ whom, it may concern.-

Be it known that I, JACOB O. JoYoE, of Dayton, in the county ofMontgomery and State of Ohio, have invented certain new and usefulImprovements in Screw-Jacks, of which the following is a specification.

My invention relates to that class of jacks commonly called telescopescrew-jacks.

The object of my invention is to provide a suitable means for operatingthe jack in cramped or narrow spaces, where only a short sweep of thelever can be obtained, all of which is to be set forth in thedescription of the accompanying drawings, making a part of thisspecification, in which- Figure 1 is a'central vertical section of myimprovement. Fig. 2 is a top plan view of the nnt,partly in section.Fig.3 shows a bent lever.

1 represents the base of thejack-frame. 2 represents the cylindricalshell. 3 represents a cylindrical nut having threads on its outerperiphery engaging with the threads on the inner periphery of the shell2, and the threads on the inner periphery of the not engage with threadson the outer periphery of the screw-rod 4.

5 represents a nut rigidly secured to the cylindrical out 3. It isprovided with screwthreads on its inner periphery, which engage with thethreads of the screw-rod 4, so that as the nut 5 is turned both theinner and outer screws serve to elevate the rod 4.

6 represents a cap on top of screw-rod 4, on which the load rests.strong nut, and one which can be readily worked, I provide the nut-head5 with three horizontal sockets, 7, which are at right angles to theradii of the screw'rod and cylindrical nut. These sockets 7 are open atboth ends, and between said sockets are recesses or openings 8 to permitthe ready engagement of a lever by means of which the nut can be easilyturned in a small space, it being obvious that three horizontal socketsopen at both ends will afford six points for the engagement of the leverat such intervals that each successive engagement of the lever willenable the nut to be advanced farther.

In order to furnish a In Fig. 2 I have shown one of the sockets 7 insection, and the other sockets areindicated by dotted lines. Betweeneach of these sockets are the openings 8, so as to allow the readyengagement of the turning-lever with said sockets.

The operation is as follows: The turninglever may be inserted in one ofthe sockets and the nut turned one-sixth of a revolution. The lever canbe removed and reversed and placed in another one of the'sockets. By theuse of the bent lever 9 (shown in Fig. 3) the knee 10 can be insertedin. any one of the sockets 7, and the not turned a little Way and thentaken out and reversed and'put in the adjacent end of the next socket,and the not turned a little more until the lever can be reversed and putin the opposite end of the last-mentioned socket, and so on, and by thismeans the nut can be turned in a contracted space. This form of nut iscompact, strong, and convenient.

My invention differs from prior jacks hav ing a screw raised and loweredby rotating a nut screw-threaded in a shell in that the several socketsextend at right angles to the radii of the nut and screw, whereby bothends of each socket are utilized for the insertion of the lever to turnthe nut.

Having described my invention, what I claim to be new is- A screw-jackcomprising the internallythreaded shell 2-, the screw-rod 4, and thecylindrical internally and externally threaded nut 3, having a head, 5,provided with three horizontal sockets, 7, andintermediate recesses orspaces, 8, said sockets being arranged'at right angles to the radii ofthe nut and open at both ends to permit the engagement therewith of anoperating-lever, substantially as described.

In testimony whereof I have hereunto set my hand.

JACOB O. JOYCE.

\Vitnesses:

ROBERT ZAHNER, J. \VA'rsoN SIMs.

